All U.S. military services use drones, not all of the same type though. They use certain drones for certain things. The MQ-4 Triton is a variant of the U.S. Air Force. It is high altitude, long endurance, designed to collect intelligence for long periods of time.
The policy is known as the "Open Door Policy."
John Hay created this idea in hopes that America and countries all over Europe could trade peacefully with China. This concept was developed in order to protect America's trade interests while also ensuring that no other country would establish a monopoly on trade with China. Within this policy, all countries would agree not to interfere with another country's trade with China.